If I buy a iphone from virgin mobile can I put it on AT&T plan?

I'm on a family plan with AT&T but I recently had my phone stolen so I have been looking to buy a new one. What I'm wondering is can I buy the iphone 4s through Virgin Mobile ( since it is cheaper) or through Best Buy( like this: http://www.bestbuy.com/...d=5689774) and then put it on my AT&T line? I want to eventually switch to Virgin Mobile but I still have about 9 more months on AT&T where I'm essentially paying for a line that I can longer use since I don't have the phone.

Haha YOU SAID VIRGIN! AS IN A PERSON WHO NEVAD HAD SX! Haha VERY FUNYYYYYYYYYYYY

No, when you buy an iPhone, it is specific to the one carrier listed, in your case Virgin Mobile. You could buy an unlocked phone, and use it on whatever carrier you would like, however I do not know much about this, or if its even legal or not. If your phone got stolen, you should be able to call up AT&T and terminate the service I would think, its worth a try if nothing else.

You can but you need to unlock the phone.